Waste products are produced during the refining of petroleum, for example, heavy oily sludges, biological sludges from wastewater treatment plants, activated sludges, gravity separator bottoms, storage tank bottoms, oil emulsion solids including slop oil emulsion solids or dissolved air floatation (DAF) float from floatation separation processes. Waste products such as these may create significant environmental problems because they are usually extremely difficult to convert into more valuable, useful or innocuous products. In general, they are usually not readily susceptible to emulsion breaking techniques and incineration, which requires the removal of substantial amounts of water typically present in these sludges, would require elaborate and expensive equipment. For this reason, they have often been disposed of in the past by the technique known as "land farming" by which the sludge is worked into the land to permit degradation by bacterial action. Resort to these methods has, however, become more limited in recent years with increasingly stringent environmental controls and increases in the amount of such waste products produced in refineries. In particular, the use of land farming is likely to encounter more stringent regulation in the future because of the potential for pollution, both of ground water and the air.
Emulsions and sludges in wastewater facilities increase treatment costs. Increased data regarding the causes of sludge and emulsion formation could lead to methods to reduce these costs.
Emulsions in refinery processes lead to sludge generation, high costs for recovering slop oils, and other problems. Although sludge yields per barrel of oil are low, the absolute quantities produced are relatively high due to a high crude oil throughput. This has led to legislation calling for extremely costly disposal methods. A clear need for an improved understanding of the refinery sludge generation problem is now apparent.
Surfactants (surface active agents) stabilize emulsions and preferentially collect at an oil/water interface. Sludges are formed when finely dispersed solids collect at the interface, further stabilizing the emulsion. Isolating or concentrating a sample of the surfactants and solids is necessary for understanding the fundamental forces that stabilize emulsions. Although solids isolation is relatively simple, isolation or concentration of the surfactants remains a problem. An understanding of the fundamental emulsion stabilization forces will suggest methods to destabilize emulsions.
Therefore, what is needed is a method of isolating or concentrating the surfactant(s) from a sludge or an oil/water emulsion so that information can be obtained about the surfactant(s) which in turn can be used to destabilize the emulsion.